11:29pm Thursday 14 November 2019

Outsmarting the superbugs

Words: Liz Porter

Monash University microbiologist Associate Professor Dena Lyras has many significant relationships in her life: with her husband, her son and daughter, and her parents. She also has an important ongoing relationship with ‘Dif’, as she and her colleagues call Clostridium difficile – a hospital superbug.

This bug has been the focus of her work as a medical researcher for more than a decade. It causes severe diarrhoea in elderly patients and has become increasingly more deadly over the past decade. It is responsible for epidemics in Canada, the UK and Australia as well as in the US, where its cost to healthcare is estimated to be as high as US$3.2 billion a year.

The bug flourishes in hospitals, where prescribed antibiotics attack the bacteria that cause particular ailments. However, these antibiotics also wipe out the ‘good’ and protective natural bacteria in a patient’s intestine, allowing ‘bad’ bugs such as Clostridium difficile to invade and thrive.

For the past 14 years, Melbourne-based Associate Professor Lyras has been on a quest to understand exactly how this bacterium works and to learn how – and why – newer versions of it have become so potent. In Australia, she is pushing for hospitals and nursing homes to start tracking the current extent of Clostridium difficile infection in their patients.

Associate Professor Lyras says Dif is not much to look at: a simple rod-shaped organism, and only visible if magnified many thousands of times through a powerful microscope. But she still regularly wakes up thinking about it and is often still pondering its workings late at night, when she emails colleagues in the ‘Dif community’, as she calls it. These fellow scientists in Perth, the UK and the US are also working on the bug.

Her husband understands, she says. “He is a microbiologist as well, so he listens. Every research scientist becomes a bit obsessed,” she adds with a laugh.

And Clostridium difficile is a tough opponent: it is intriguingly hardy.

“It won’t grow in the presence of oxygen, so you’d think it would be easy to kill,” Associate Professor Lyras says.

But the bug makes two versions of itself: the vegetative cell that makes people sick and the ‘spore’, which is the key to its transmission. It is this tough seed-like spore that survives in oxygen and resists many antibacterial chemicals.

“When people are infected, the bacteria make lots of spores, which spread very efficiently. Once Dif is in the hospital environment it is almost impossible to get rid of it.”

Scary? “And clever,” Associate Professor Lyras says. “I am driven by curiosity. These tiny little entities can do so much damage and we can’t even see them without very powerful imaging equipment … and they constantly change. As soon as you find a way to fight them they find a way to get around it, and really quickly.”

Read the full article and find out more about other research breakthroughs in the MONASH: Delivering Impact online edition.

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